For the purpose of uniform brightness and lack of distortion of a picture displayed by a television picture tube, it is highly desirable that the face plate or viewing panel of such a tube have, in the viewing or picture display area thereof, a uniform thickness. There is disclosed, for example, in copending application, Ser. No. 579,883, filed May 22, 1975 by Lawrence B. Hausheer and assigned to the same assignee as the present application, a television picture tube envelope including a face plate having, at least in the viewing area thereof, a substantially uniform thickness throughout such area. It is now known that stresses across the face plate of television picture tubes are greatest at the ends of the minor axis of the face plate, least at the ends of the diagonal axis thereof and of an intermediate value at the ends of the major axis of the face plate. Accordingly, in order to reduce the weight of a television picture tube and attain an economic advantage by the saving of the quantity of glass used in manufacturing the face plate of such a tube, the present invention, using a reduced quantity of glass in the viewing area of a television picture tube face plate was developed, such a reduction in such quantity of glass used being attained by a reduction in the thickness of the glass in said viewing area which is found to be possible due to a minimum stress in the glass of such area.
It is, therefore, an object of the present invention to provide a novel face plate or viewing panel for a television picture tube or tube envelope, such face plate having a configuration such that a lesser quantity of glass than normally used may be used in the manufacture thereof and a lighter weight face plate thereby provided.
It is another object of the present invention to provide a novel face plate or viewing panel for a television picture tube or tube envelope, such face plate providing an economic advantage due to savings in the quantity of glass required for manufacture of the face plate or viewing panel.
Other objects and characteristic features of the invention will become apparent as the description proceeds.